Formaldehyde free binder compositions with urea-aldehyde reaction products

ABSTRACT

Binder compositions are described that contain (1) a reducing sugar and (2) a reaction product of a urea compound and an aldehyde-containing compound. A specific example of the binder compositions include dextrose and an imidazolidine compound such as 4,5-dihydroxyimidazolidin-2-one. The binder compositions may be applied to collections of fibers and cured to form a fiber-containing composite, such as fiberglass insulation.

CROSS-REFERENCES TO RELATED APPLICATIONS

Not Applicable

BACKGROUND OF THE INVENTION

Organic binders for composite fiber products such as fiberglassinsulation are moving away from traditional formaldehyde-basedcompositions. Formaldehyde is considered a probable human carcinogen, aswell as an irritant and allergen, and its use is increasingly restrictedin building products, textiles, upholstery, and other materials. Inresponse, binder compositions have been developed that reduce oreliminate formaldehyde from the binder composition.

One type of these formaldehyde-free binder compositions rely onesterification reactions between carboxylic acid groups in polycarboxypolymers and hydroxyl groups in alcohols. Water is the main byproduct ofthese covalently crosslinked esters, which makes these binders moreenvironmentally benign, as compared to traditional formaldehyde-basedbinders. However, these formaldehyde-free binder compositions also makeextensive use of non-renewable, petroleum-based ingredients. Thus, thereis a need for formaldehyde-free binder compositions that rely less onpetroleum-based ingredient.

As an abundant and renewable material, carbohydrates have greatpotential to be an alternative to petroleum-based binders. Carbohydratesare already used as a component of some types for binders, such asMaillard binders that contain reaction products of reducing sugarcarbohydrates and amine reactants. However, many types ofcarbohydrate-containing binders tend to become brittle when cured andform excessive particulates when the insulation is folded or compressed.Some carbohydrate-containing binders are also prone to accelerateddegradation in humid environments and thus require additionalconditioning and additives to improve their moisture/water resistance.Thus, there is a need to improve the stability and water resistance ofcarbohydrate-containing binder compositions to levels that are similarto or better than those of conventional, petroleum-based bindercompositions. These and other issues are addressed in the presentapplication.

BRIEF SUMMARY OF THE INVENTION

Binder compostions are described that may include carbohydrates and acrosslinking agent made from the reaction product of a urea compound andan aldehyde-containing compound. Examples of the crosslinking agentsinclude imidazolidine compounds made from the reaction product of urea(i.e., H₂N—CO—NH₂) and/or substituted ureas with diformaldehydecompounds such as glyoxal. A specific example of an imidazolidinecrosslinking agent that may be used in the present binder compositionsis 4,5-dihydroxyimidazolidin-2-one, which has the chemical structure:

The binder composition may be applied to a group of fibers to form anpre-cured amalgam of binder composition and fibers. The amalgam may thenbe exposed to curing conditions (e.g., heating) to facilitate the curingof the binder and formation of a fiber-containing composite. During thecuring stage, the crosslinking agent crosslinks the reducing sugar toform a polymeric matrix that adheres the fibers together in thefiber-containing composite. Examples of these composites include fiberinsulation (e.g., fiberglass insulation) for piping, ducts, buildings,and other construction applications.

Embodiments include binder compositions containing (1) a reducing sugarand (2) a reaction product of a urea compound and an aldehyde-containingcompound. The binder composition may be applied to a group of fibers andexposed to curing conditions to form a fiber-containing composite offibers bound by the cured binder.

A more specific embodiment of the binder composition may includedextrose as the reducing sugar, and 4,5-dihydroxyimidazolidin-2-one asthe reaction product of a urea compound (in this case H₂N—CO—NH₂) andglyoxal (OHC—CHO). When the dextrose and 4,5-dihydroxyimidazolidin-2-oneare exposed to binder curing conditions, the4,5-dihydroxyimidazolidin-2-one crosslinks the dextrose (and polymerizedforms of dextrose) to make the cured binder.

Embodiments further include fiber-containing composites containing wovenor non-woven fibers and a cured binder formed from a binder compositionthat includes (1) reducing sugar and (2) a crosslinking agent that is areaction product of a urea compound and an aldehyde-containing compound.The fibers may be one or more types of fibers chosen from glass fibers,mineral fibers, and organic polymer fibers (among others). Non-wovenglass fibers may be included in composites for fiberglass insulation.

Embodiments still further include methods of binding fibers, where themethods include the step of applying a binder composition to a mat ofwoven or non-woven fibers, and then curing the binder compositionapplied to the fibers to make a fiber-containing composite. The bindercomposition may include a reducing sugar and a crosslinking agent formedas a reaction product between a urea compound and an aldehyde-containingcompound, as described above.

Additional embodiments and features are set forth in part in thedescription that follows, and in part will become apparent to thoseskilled in the art upon examination of the specification or may belearned by the practice of the invention. The features and advantages ofthe invention may be realized and attained by means of theinstrumentalities, combinations, and methods described in thespecification.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the remaining portions of thespecification and the drawings wherein like reference numerals are usedthroughout the several drawings to refer to similar components. In someinstances, a sublabel is associated with a reference numeral and followsa hyphen to denote one of multiple similar components. When reference ismade to a reference numeral without specification to an existingsublabel, it is intended to refer to all such multiple similarcomponents.

FIG. 1 shows a graph of dogbone tensile strength test results fordifferent mole ratios of reducing sugar to crosslinking agent;

FIGS. 2A-C show simplified illustrations of exemplary compositematerials according to embodiments of the invention;

FIG. 3 depicts a simplified schematic of an exemplary fabrication systemfor making the fiber-containing composites according to embodiments ofthe invention;

FIG. 4 is a picture of a cured dogbone composite placed in an Instrontensile strength measuring instrument; and

FIG. 5 is a graph with dogbone tensile strength test results for bindercomposites.

DETAILED DESCRIPTION OF THE INVENTION

The present binders include renewable materials such as simplecarbohydrates (e.g., dextrose, fructose) crosslinked by a reactionproduct of a urea compound and an aldehyde-containing compound. The ureacompound may be a substituted our unsubstituted urea having the formula:

where R₁, R₂, R₃, and R₄ are independently chosen from a hydrogen moiety(H), an alkyl group, an aromatic group, an alcohol group, an aldehydegroup, a ketone group, a carboxylic acid group, and an alkoxy group.Exemplary alkyl groups include straight-chained, branched, or cyclichydrocarbons of varying size (e.g., C₁-C₁₂, C₁-C₈, C₁-C₄, etc.).Exemplary aromatic (i.e., aryl) groups include substituted orunsubstituted phenyl moieties, among other aromatic constituents.Exemplary alcohol groups include —ROH, where R may be a substituted orunsubstituted, saturated or unsaturated, branched or unbranched, cyclicor acyclic, organic moiety. For example, R may be —(CH2)_(n)—, where nmay be 1 to 12. Exemplary alcohols may also include polyols having twoor more hydroxyl groups (—OH) in alcohol group. Exemplary aldehydegroups include —RC(═O)H, where R may be a monovalent functional group(e.g., a single bond), or a substituted or unsubstituted, saturated orunsaturated, branched or unbranched, cyclic or acyclic, organic moiety,such as —(CH2)_(n)—, where n may be 1 to 12. Exemplary ketone groups mayinclude —RC(═O)R′ where R and R′ can be variety of carbon containingconstituents. Exemplary carboxylic acid groups may include —R—COOH,where R may be a monovalent functional group, such as a single bond, ora variety of carbon-containing constituents. Exemplary alkoxy groupsinclude —OR_(x), where R_(x) is an alkyl group.

The aldehyde-containing compound may contain one or more aldehydefunctional groups. Exemplary aldehyde-containing compounds includeacetaldehyde, propanaldehyde, butyraldehyde, acrolein, furfural,glyoxal, gluteraldehyde, and polyfurfural among others. Exemplaryaldehyde-containing compounds may also include substituted glyoxalcompounds having the formula:

where R₅ and R₆ may be independently hydrogen (H), an alkyl group, anaromatic group, an alcohol group, an aldehyde group, a ketone group, acarboxylic acid group, and an alkoxy group, among other groups.

The reaction products of the urea compound and the aldehyde-containingcompound may include an imidazolidine compound having the formula:

where R₇, R₈, R₉, and R₁₀ are independently, —H, —OH, —NH₂, an alkylgroup, an aromatic group, an alcohol group, an aldehyde group, a ketonegroup, a carboxylic acid group, and an alkoxy group. In one specificexample of the reaction between urea and glyoxal, the reaction productmay be 4,5-dihydroxyimidazolidin-2-one.

The reaction product of the urea compound and the aldehyde-containingcompound may act as a crosslinking agent for the reducing sugar. Duringa curing stage the crosslinking agent can bond to two or more reducingsugars (either polymerized or unpolymerized) to form a crosslinked,polymeric cured binder.

The reducing sugar may be any sugar having an aldehyde group, or aketone group that is capable of isomerizing to produce an aldehydegroup. Exemplary reducing sugars include monosaccharaides such asglucoses (e.g., dextrose), fructose, glyceraldehyde, and galactose. Theyalso include polysaccharaides such as lactose, maltose, xylose, andamylose, among others. The binder compositions may include a singlereducing sugar or a combination of two or more reducing sugars as thereducing sugars in the composition.

The molar ratio of the (1) crosslinking reaction product of the ureacompound and the aldehyde-containing compound to (2) the reducing sugargenerally ranges from 1:2 to 1:50. Exemplary ratios of crosslinkingagent to reducing sugar include a range from 1:4 to 1:10. FIG. 1 shows agraph of dogbone composite tests of tensile strength for bindercompositions using a reaction product of urea [CO(NH₂)₂] and glyoxal[OCHCHO] as the crosslinking agent and dextrose [C₆H₁₂O₆] as thereducing sugar. The graph shows the tensile strength of the compositespeaking at 4 to 5 moles of dextrose normalized for 1 mole of thecrosslinking agent. This translates into a peak tensile strength at(crosslinking agent):(reducing sugar) mole ratios between 1:4 and 1:5.The tensile strength shows no significant increases for higher relativemoles of the dextrose relative to the urea-glyoxal crosslinking agent.While not wishing to be bound by a particular theory, it is believedthat the molar ratio between 1:4 and 1:10 facilitates the highestcrosslinking density in the cured binder.

In addition to the reducing sugars, the present binder compositions mayalso include non-reducing sugars and celluloses, such as starches,modified starches, celluloses, modified celluloses, and dextrins (e.g.,cyclodextrins and maltodextrins), among others.

The binder composition may further include one or more additionalcomponents such as adhesion prompters, oxygen scavengers, solvents,emulsifiers, pigments, organic and/or inorganic fillers, flameretardants, anti-migration aids, coalescent aids, wetting agents,biocides, plasticizers, organosilanes, anti-foaming agents, colorants,waxes, suspending agents, anti-oxidants, and secondary crosslinkers,among other components. In some instances, some or all of the additionalcomponents are pre-mixed with the binder composition before it isapplied to fibers and cured. In additional instances, some or all of theadditional components may be introduced to the curable, curing, and/orcured fiber-containing composite during or after the initial bindercomposition is applied to the fibers.

The binder compositions may also include one or more catalysts toincrease the rate of the crosslinking reactions between the reducingsugars and crosslinking agents when the composition is exposed to curingconditions. Exemplary catalysts may include alkaline catalysts andacidic catalysts. The acidic catalysts may include Lewis acids(including latent acids and metallic salts), as well as protic acids,among other types of acid catalysts. Lewis acid catalysts may a salt ofa deprotonized anion such as a sulfate, sulfite, nitrate, nitrite,phosphate, halide, or oxyhalide anion in combination with one or moremetallic cations such as aluminum, zinc, iron, copper, magnesium, tin,zirconium, and titanium. Exemplary Lewis acid catalysts include aluminumsulfate, ferric sulfate, aluminum chloride, ferric chloride, aluminumphosphate, ferric phosphate, and sodium hypophosphite (SHP), amongothers. Exemplary latent acids include acid salts such as ammoniumsulfate, ammonium hydrogen sulfate, mono and dibasic ammonium phosphate,ammonium chloride, and ammonium nitrate, among other latent acidcatalysts. Exemplary metallic salts may include organo-titanates andorgano-zirconates (such as those commercially manufactured under thetradename Tyzor® by DuPont), organo-tin, and organo-aluminum salts,among other types of metallic salts. Exemplary protic acids includesulfuric acid, phosphoric acid, hydrochloric acid, nitric acid, sulfonicacid compounds (i.e., R—S(═O)₂—OH) such as p-toluenesulfonic acid andmethanesulfonic acid, and carboxylic acids, among other protic acids.Catalyst compositions may also include combinations of two or morecatalysts, for example the combination of ammonium sulfate anddiammonium phosphate.

Exemplary concentrations of the catalyst (or combination of catalysts)in the binder composition may have a range from about 1 wt. % to about20 wt. % of the composition. For example, the catalyst concentration mayrange from about 1%, 2%, 3%, 4%, 5%, 6%, 7%, etc., on the low end, and10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20 wt. % on thehigh end. Exemplary catalyst concentrations may include about 5 wt. %,about 7.5 wt. %, about 8 wt. %, about 9 wt. %, and about 10 wt. %, amongother concentrations.

The pH of the present binder compositions may vary depending upon thetypes and relative concentrations of the components used. Typically thepH of the present binder compositions are slightly acidic to alkalinewith a pH range of about 6 to 8 (e.g., 6.5 to 7.5). The bindercompositions have a pH that creates relatively little or no acid-basedcorrosion of metal fabrication equipment.

The binder compositions may be used to make fiber-containing compositesthat include woven or non-woven fibers bound together by a cured matrixof the binder. The fibers in the composite may include one or more typesof fibers chosen from glass fibers, carbon fibers, mineral fibers, andorganic polymer fibers, among other kinds for fibers. At the conclusionof the curing stage, the cured binder may be present as a secure coatingon the fiber mat at a concentration of approximately 0.5 to 50 percentby weight of the composition, for example the cured binder may bepresent at concentration of approximately 1 to 10 percent by weight ofthe composition.

The fiber-containing composites may take a variety of forms, for exampleconstruction materials including piping insulation, duct boards (e.g.,air duct boards), and building insulation, reinforcement scrim, androofing membranes, among other construction materials. Additionalexamples may include loose-fill blown insulation, duct liner, duct wrap,flexible duct media, pipe insulation, tank insulation, rigid plenumliner, textile duct liner insulation, equipment liner, oven insulation,elevated temperature board, elevated temperature wrap, elevatedtemperature panel, insulation batts and rolls, heavy density battinsulation, light density batt insulation, exterior foundationinsulation board, and marine hull insulation, among other materials. Thecomposites can also find use in printed circuit boards, batteryseparators, and filter stock, among other applications.

FIG. 2A-C illustrate some of these exemplary composite materials. FIG.2A is a simplified schematic of an exemplary fiber-containing battmaterial 202 that may be used for building insulation. The material 202may include a batt 203 of non-woven fibers held together by the binder.The fibers may be glass fibers used to make fiberglass insulation (e.g,low-density or high-density fiberglass insulation), or a blend of two ormore types of fibers, such as a blend of glass fibers and organicpolymer fibers, among other types of fibers. In some examples, a facer204 may be attached to one or more surfaces of the batt 203.

FIG. 2B is a simplified schematic of an exemplary fiber-containingcomposite board 206 that may be used as an insulation board, duct board,elevated temperature board, etc. The fibers in board 206 may includeglass fibers, organic polymer fibers, carbon fibers, mineral fibers,metal fibers, among other types of fibers, and blends of two or moretypes of fibers.

FIG. 2C is a simplified schematic of an exemplary fiber-containingflexible insulation material 208 that may be used as a wrap and/or linerfor ducts, pipes, tanks, equipment, etc. The fiber-containing flexibleinsulation material 208 may include a facer 210 attached to one or moresurfaces of the fiber material 212. Exemplary materials for the facer210 may include fire-resistant foil-scrim-kraft facing.

Specific examples of fiber-containing composites that use the presentbinder compositions include low-density fiberglass insulation (e.g.,less than about 0.5 lbs/ft³) and high-density fiberglass insulation.

The present binder compositions may be used in methods of binding fibersto make the fiber-containing composites. The fiber-containing compositesmay include fibers of one or more types, such as glass fibers, carbonfibers, and organic polymer fibers, among other types of fibers. Thebinder compositions used to make the composites may include a reducingsugar and a reaction product of a urea compound and analdehyde-containing compound as described above. The methods may includethe step of applying the binder composition to a mat of woven ornon-woven fibers to make a curable binder-fiber amalgam. The curableamalgam is then cured to form the fiber-containing composite of fibersbound together by the cured binder.

The step of applying the binder composition to the fibers may be done bya variety of techniques including spraying, spin-curtain coating,curtain coating, and dipping-roll coating. The composition can beapplied to freshly-formed fibers, or to fibers that have been cooled andprocessed (e.g., cut, coated, sized, etc.). The binder may be providedto the applicator as a premixed composition or may be supplied to theapplicator in separate solutions for the crosslinking agent and thereducing sugar component. In some instances where the binder compositionincludes a solvent, a portion or all of the solvent may be removed fromthe composition before or after its application on the fibers.

The step of curing the binder composition may include exposing thecomposition applied to the fibers to an environment conducive to curing.For example, the curable amalgam of fibers and binder composition may beheated to a binder curing temperature. Exemplary binder curingtemperatures may include a temperature range from 100° C. to 250° C. Thecuring amalgam may be heated to the curing temperature for a period of 1minute to 100 minutes (e.g., 20 minutes).

The curing step may produce the finished fiber-containing composite,such as fiberglass insulation. In some exemplary methods, additionalagents like an anti-dusting agent may be applied during or following thecuring step.

FIG. 3 shows a simplified schematic of an exemplary fabrication system300 for making the fiber-containing composites described above. Thesystem 300 includes fiber supply unit 302 that supplies the fibers forthe composite. The fiber supply unit 302 may be filled with pre-madefibers, or may include equipment for making the fibers from startingmaterials such as molten glass or organic polymers. The fiber supplyunit 302 deposits the fibers 304 onto a porous conveyor belt 306 thattransports the fibers under the binder supply unit 308.

The binder supply unit 308 contains a liquid uncured binder composition310, that is deposited onto the fibers 304. In the embodiment shown, thebinder composition 310 is spray coated onto the fibers 304 with spraynozzles 312, however, other application techniques (e.g., curtaincoating, dip coating, etc.) may be used in addition to (or in lieu of)the spray coating technique illustrated by nozzles 312.

The binder composition 310 applied on fibers 304 forms a fiber andbinder amalgam on the top surface of the conveyor belt 306. The belt 306may be perforated and/or porous to allow excess binder composition 310to pass through the belt 306 to a collection unit (not shown) below. Thecollection unit may include filters and circulation pumps to recycle atleast a portion of the excess binder back to the binder supply unit 308.

The conveyor belt 306 transports the amalgam to an oven 314 where it isheated to a curing temperature and the binder composition starts tocure. The temperature of the oven 314 and the speed of the conveyor belt306 can be adjusted to control the curing time and temperature of theamalgam. In some instances, process conditions may set to completelycure the amalgam into the fiber-containing composite. In additionalinstances, process conditions may be set to partially cure the amalgaminto a B-staged composite.

The amalgam may also be compressed prior to or during the curing stage.System 300 shows an amalgam being compressed by passing under a plate316 that tapers downward to decrease the vertical space available to thecuring amalgam. The amalgam emerges from under the plate 316 in acompressed state and has less thickness than when it first made contactwith the plate. The taper angle formed between the plate 316 andconveyor belt 306 can be adjusted to adjust the level of compressionplaced on the amalgam. The partially or fully cured composite thatemerges from under plate 316 can be used for a variety of applications,including construction materials such as pipe, duct, and/or wallinsulation, among other applications.

EXAMPLES Example 1A Tensile Strength Testing of Dextrose BinderComposites

Comparative tensile strength tests were conducted on composites madewith an exemplary dextrose/urea-glyoxal binder composition andcomposites made with a standard commercial polyacrylic bindercomposition. The dextrose/urea-glyoxal composition was prepared bymixing 60 g of urea, 145 g of a 40 wt % solution of glyoxal, at atemperature of 90° C. for about 120 minutes. The urea and glyoxal reactto form crosslinking agents for the binder composition, including cyclicurea-glyoxal compounds (e.g., 4,5-dihydroxyimidazolidin-2-one). Next,918 g of water and 989 g of dextrose monohydrate (900 g active) wereadded to the reacted urea-glyoxal solution to form the uncured bindercomposition for making the dogbone composite. To this solution was added76.4 g ammonium sulfate as a catalyst. The uncured polyacrylic bindercomposition was made by mixing a commercial polyacrylic acid (QRXP-1765acrylic resin from Dow Chemical) with triethanol amine that acted as acrosslinking agent.

Each of the binder compositions was formulated into 25 g samples havinga 50 wt. % solids level and mixed with 1000 g of glass beads to makeuncured composites. Roughly 1 ounce samples of the uncured compositeswere then spread into dogbone molds and pressed in the molds at apressure of about 10,000 lbs. The dogbone samples were then releasedfrom the molds and heated at about 400° F. for about 20 minutes to formcured dogbone composites. The cured dogbone composites were roughly 25mm wide and 6 mm thick.

The cured dogbone composites were tested for tensile strength in both anunaged condition and after being aged in a high humidity atmosphere. Theunaged composites were taken directly from the curing oven and placed inan Instron tensile strength testing instrument (Harry W. DietertCo.—Tensile Core Grip Assembly Part No. 610-7CA) as shown in FIG. 4. Theaged composites were taken from the curing oven and placed for 24 hoursin a humidifying oven set at approximately 95% humidity and 120° F.After the aged samples were cooled for approximately 8 hours, they wereplaced in the Instron instrument to test their tensile strength.

FIG. 5 is a graph showing the dogbone tensile strength test results forthe dextrose/urea-glyoxal binder under unaged and humid-aged conditions,as well the strength test results for the comparative composite madefrom the commercial polyacrylic acid binder. The results demonstratethat the unaged dextrose/urea-glyoxal binder and an almost identicaltensile strength as the unaged commercial polyacrylic binder at 2.9 MPa.When both samples were aged at 120° F. and 95% humidity for 24 hours,the aged dextrose/urea-glyoxal binder showed significantly highertensile strength (2.15 MPa) compared with the aged polyacrylic binder(1.6 MPa).

Example 1B Tensile Strength Testing of Fructose/Dextrose BinderComposites

Additional tensile strength tests were conducted on composites made withexemplary binder compositions that included combinations of fructose anddextrose reacted with a urea-glyoxal crosslinking agent. A firstfructose+dextrose/urea-glyoxal binder composition was prepared by mixing60 g of urea, 145 g of a 40 wt % solution of glyoxal, at a temperatureof 90° C. for about 120 minutes. The urea and glyoxal react to formcrosslinking agents for the binder composition, including cyclicurea-glyoxal compounds (e.g., 4,5-dihydroxyimidazolidin-2-one). Next,918 g of water and 989 g of 42 wt. % fructose and 55 wt. % dextrosemonohydrate were added to the reacted urea-glyoxal solution to form theuncured binder composition for making the dogbone composite. To thissolution was added 76.4 g ammonium sulfate as a catalyst. A secondfructose+dextrose/urea-glyoxal binder composition was prepared using thesame components and preparation method, except the fructose:dextroseratio was changed to 55 wt. % fructose and 42 wt. % dextrose. Dogbonecomposites were prepared from both the first and secondfructose+dextrose/urea-glyoxal binder compositions in the same method asdescribed in Example 1A above. The dogbone tensile strength test resultsdemonstrated similar tensile strengths for thefructose+dextrose/urea-glyoxal binder compositions as the dextrose-onlycompositions.

Example 2 Preparation of an Exemplary Glass-Fiber Composites

A glass-fiber composite was made from a dextrose/urea-glyoxal bindercomposition and a nonwoven glass fiber mat. Preparation of the bindercomposition started by mixing 60 kg or urea into a 145 kg aqueousglyoxal solution (40 wt. % glyoxal (58 kg on dry basis)) at roomtemperature until the urea dissolved. The urea-glyoxal solutiontemperature was then increased to 80° C. and kept at 80-85° C. for 2hours while stirring the solution at 500 rpm to facilitate the reactionof the urea and glyoxal. At the end of the reaction period, a 57 wt. %solution of the urea-glyoxal crosslinking agent was formed.

918 kg or water and 989 kg of dextrose monohydrate (900 kg active) wereadded to the crosslinking solution and the combined mixture was stirreduntil the dextrose dissolved. The mole ratio of urea:glyoxal:dextrose inthe solution was 1:1:5. 76.4 kg of ammounium sulfate was added to thesolution as a catalyst, and stirred until the catalyst dissolved to makethe binder composition.

Manufacture and Testing of R19 Fiberglass Insulation Batts

The binder composition was spray coated onto a nonwoven glass-fiber matmade from blown filaments of sodium borosilicate glass having diametersranging from about 1 to 10 μm and lengths ranging from of about 5 to 100mm. The amalgam of the fibers and binder composition was then conveyedthrough a curing oven operated at a temperature of 150° C. to 350° C. toheat the amalgam to a curing temperature for about 30 seconds to 3minutes. The bat of glass fibers held together by the cured binderemerged from the oven with an approximate thickness of about 3 to 4 cmand a nominal weight of about 440 g/m² and density of about 11.2 kg/m³.

The cured bat was used to make R-19 building insulation. The droop(rigidity) and recovery of the batts were evaluated under unagedconditions, as well as after aging for 7 and 14 days at 120° F. and 95%humidity. The performance of the batts made with thedextrose-urea-glyoxal binder composition was compared to bats made withconventional binder compositions. The comparative tests found the unagedbatts made with the dextrose-urea-glyoxal binder composition had 10%improved rigidity (i.e., lower sag) compared with comparable batts madewith a conventional binder composition (acrylic), and the aged battsshowed an even larger 20% improvement in rigidity (lower sag). Thisimprovement in the rigidity of the batts made with thedextrose-urea-glyoxal binder composition did not result in anydiminishment of their recovery performance compared to the conventionalbatts. In addition, the emissions of volatile organic compounds (VOCs)from batts made with the urea/glyoxal/dextrose binder compositions weresignificantly lower than batts made with the conventional acrylic bindercompositions. No release of formaldehyde was detected from theurea/glyoxal/dextrose batts. Table 1 below summarizes the droop,recovery, and VOC emissions results for the various sample batts tested:

TABLE 1 Droop and Recovery Results for R19 Insulation Batts Droop VOC(Rigidity) - Recovery - Emissions - Sample [Inches] [Inches] [lb/hour]Urea/glyoxal/dextrose 2.1 6.7 0.8 binder composition (unaged)Urea/glyoxal/dextrose 3.4 6.0 N/A binder composition (Aged 7 days)Urea/glyoxal/dextrose 3.5 6.0 N/A binder composition (Aged 14 days) PFBinder (unaged) 2.5 6.5 0.9 PF Binder (Aged 7 days) 4.2 6.1 N/A PFBinder (Aged 14 days) 4.5 6.0 N/A

Manufacture and Testing of Duct Board

The present dextrose-urea-glyoxal binder compositions are also used tomake duct board. Two compositions were independently prepared using 145kg of 40 wt. % aqueous glyoxal mixed with 60 kg urea and 989 kg dextrosemonohydrate. 76.4 kg of ammonium sulfate was added to one of thecompositions, while 50 kg of ammonium sulfate and 50 kg of diammoniumphosphate was added to the other. Each of the binder compositions wasused to make 1.9 cm thick duct board having a binder content of 18 wt %and density of 700 kg/m3 using standard process conditions (e.g., curetemperature of 500-550° F.).

The structural characteristics and volatile organic compound (VOC)emissions of the duct boards were tested and compared to duct board madewith a conventional phenol-formaldehyde (PF) binder composition. Theresults showed that the droop (rigidity) and El modulus of the ductboards made with the urea/glyoxal/dextrose binder compositions improvedby about 20% compared to the duct boards made with the conventional PFbinder composition. The present duct boards also had significantlyreduced VOC emissions compared to the PF board. The improvements in theduct boards' structural characteristics were similar for theurea/glyoxal/dextrose binder compositions that included ammonium sulfate[(NH₄)₂SO₄] alone versus the combination of ammonium sulfate anddiammonium phosphate [(NH₄)₂SO₄ and (NH₄)₂HPO₄]. Table 2 belowsummarizes the droop, El modulus, and VOC emissions results for thevarious duct boards tested:

TABLE 2 Droop and El Modulus Results for Duct Boards Droop (Rigidity) -El Modulus - Sample [Inches] [N · m²?] Urea/glyoxal/dextrose binder 2.5183 composition with (NH₄)₂SO₄ alone Urea/glyoxal/dextrose binder 1.3153 composition with (NH₄)₂SO₄ and (NH₄)₂HPO₄ Conventional Phenol- 2.5145 Formaldehyde binder Composition

Additional Characteristics of the Present Insulation Batts and DuctBoards

Fiberglass insulation batts and duct boards made with the presenturea/glyoxal/dextrose binder compositions were measured on a number ofcharacteristics described in Table 3 below. For all the characteristics,the batts and boards met or exceeded current standards requirements forresidential and commercial building materials set by the AmericanSociety for Testing and Materials (ASTM) and Underwriters Laboratory(UL).

TABLE 3 Characteristics of R19 Insulation Batt and Duct BoardsCharacteristic R19 Insulation Batt Duct Board Density 0.25-0.75 lbs/ft³2.0-6.0 lbs/ft³ Loss on Ignition (LOI) 3 wt. %-6 wt. % 15 wt. %-22 wt. %Tensile Strength 0.35-1.0 psi Thickness Recovery 5 inches-7 inches 0.9inches-1.1 inches Dust Testing 10-50 g/10,000 ft² 0.03-0.3 g/lb WaterAbsorption >0.5 wt % >5 wt. % Flexural Rigidity (E · l) <400 ElStiffness-Rigidity ≤5 inches for 36 inch span Hot Surface PerformanceMeets C411 Requirements Corrosivity on Steel Mass loss corrosion rate <5ppm Mass loss corrosion rate chloride reference solution <5 ppm chloridereference (ASTM C1617) solution (ASTM C1617) Smoke Development on Flamespread of <25, and smoke Flame spread of <25, and Ignition developed <50using ASTM smoke developed <50 using E84; ASTM E84 Classified asNon-Combustible based on ASTM E136.

Having described several embodiments, it will be recognized by those ofskill in the art that various modifications, alternative constructions,and equivalents may be used without departing from the spirit of theinvention. Additionally, a number of well-known processes and elementshave not been described in order to avoid unnecessarily obscuring thepresent invention. Accordingly, the above description should not betaken as limiting the scope of the invention.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimits of that range is also specifically disclosed. Each smaller rangebetween any stated value or intervening value in a stated range and anyother stated or intervening value in that stated range is encompassed.The upper and lower limits of these smaller ranges may independently beincluded or excluded in the range, and each range where either, neitheror both limits are included in the smaller ranges is also encompassedwithin the invention, subject to any specifically excluded limit in thestated range. Where the stated range includes one or both of the limits,ranges excluding either or both of those included limits are alsoincluded.

As used herein and in the appended claims, the singular forms “a”, “an”,and “the” include plural referents unless the context clearly dictatesotherwise. Thus, for example, reference to “a process” includes aplurality of such processes and reference to “the fiber” includesreference to one or more fibers and equivalents thereof known to thoseskilled in the art, and so forth.

Also, the words “comprise,” “comprising,” “include,” “including,” and“includes” when used in this specification and in the following claimsare intended to specify the presence of stated features, integers,components, or steps, but they do not preclude the presence or additionof one or more other features, integers, components, steps, acts, orgroups.

What is claimed is:
 1. A binder composition comprising: a reducing sugarmonosaccharide; a crosslinking agent that is a reaction product of aurea compound and an aldehyde-containing compound, wherein thecrosslinking agent and the reducing sugar have a molar ratio of 1:2 to1:50; and a catalyst for catalyzing a crosslinking reaction between thereducing sugar and the crosslinking agent, wherein the catalystcomprises a sulfonic acid compound.
 2. The binder composition of claim1, wherein the urea compound comprises H₂N—CO—NH₂.
 3. The bindercomposition of claim 1, wherein the aldehyde-containing compound isglyoxal.
 4. The binder composition of claim 1, wherein the reactionproduct of the urea compound and the aldehyde-containing compoundcomprises 4,5-dihydroxyimidazolidin-2-one.
 5. The binder composition ofclaim 1, wherein the reducing sugar monosaccharide comprises dextrose.6. The binder composition of claim 1, wherein the sulfonic acid compoundcomprises at least one of p-toluene sulfonic acid or methane sulfonicacid.
 7. The binder composition of claim 1, wherein the compositionfurther comprises one or more non-reducing carbohydrates chosen fromstarch, modified starch, cellulose, modified cellulose, and dextrins. 8.The binder composition of claim 1, wherein the composition furthercomprises one or more additional components chosen from adhesionpromoters, flame retardants, organic fillers, inorganic fillers, waxes,colorants, and release agents.
 9. The binder composition of claim 1,wherein a molar ratio of the reaction product to the reducing sugar is1:6 to 1:10.
 10. A binder composition comprising: dextrose;4,5-dihydroxyimidazolidin-2-one, wherein a molar ratio of the4,5-dihydroxyimidazolidin-2-one to the dextrose ranges from 1:2 to 1:50,and a catalyst comprising a sulfonic acid compound, wherein the catalystcomprises 1 wt. % to 20 wt. % of the binder composition.
 11. The bindercomposition of claim 10, wherein the sulfonic acid compound comprises atleast one of p-toluene sulfonic acid or methane sulfonic acid.
 12. Abinder composition comprising: a reducing sugar monosaccharide; acrosslinking agent comprising a reaction product of a urea compound andan aldehyde-containing compound, wherein the crosslinking agent and thereducing sugar have a molar ratio of 1:2 to 1:50; and a catalystcomprising 1 wt. % to 20 wt. % of the binder composition, wherein thecatalyst comprises at least one of p-toluene sulfonic acid or methanesulfonic acid.